Thumim



2 Sheets-Sheet 1 THA/A5 C. THUMIM EAM-U-C 076// l KNIFE CHANGING CONTROLS FOR PAPER CUTTING MACHINES ibi;

@aff/Di A7/17,0

March 17 1964 Filed Deo. 9, 1960 March 17, 1964 c. THUMIM 3,124,989

KNIFE CHANGING CONTROLS ECE PAPER CUTTING MACHINES Filed Dec. 9, 1960 2 Sheets-Sheet 2 EFL-3 5.' 'I IA LT ll 1 l I I afnews/we, i155@ 175 fame/v ETI United States Patent 3,124,989 KNIFE CHANGENG CGNTROLS FOR PAPER CUTTING MACHINES Carl Thumim, Westbury, N.Y., assigner to Mireille-Goss- Dexter, Incorporated, Chicago, Ill., a corporation of Delaware Filed Dec. 9, 1960, Ser. No. 74,993 2 Claims. (Cl. 33-399) This invention relates lto knife clanging devices for use in guillotine type paper cutters and more particularly to an arrangement for effecting contr-ol during the course of the knife-changing procedure.

In modern practice in the use of guillotine paper cutters, especially of the hydraulic powered clamp type, there has developed a system and an arrangement whereby the knife to be installed need not lbe raised or carried to the knife-bar by human effort, but can be temporarily attached to the cla-mp to the lifted up to the knife-bar for subsequent attachment thereto by means of screws.

-In the course of changing the knives of guillotine paper cutters it is essential that the knife-actuating mechanism be completely out of power operation and it is also essential that the knife being installed on the knife-bar be raised slowly s-o as to avoid shock stresses.

In general, the knife blade to be installed is carried on the clamp by means of a pair of washers which engage the knife bevel and hold it tightly against the front surface of the clamp. Such washers are normally carried in a particular storage place on the machine and are coupled with control circuitry. Thus, when the washers are removed from storage and attached .'to the clamp for securing the knife thereto, the circuitry is operative to prevent knife-'bar power actuation and also controls the clamp-actuating mechanism so as to raise it slowly, with the knife carried on it, to fully raised position to meet the knife bar. In prior art systems, generally, the clamp is raised by release of the foot treadle very cautiously so as to insure slow upward movement of the clamp. However, all operators `do not have the necessary skill in foot treadle release in order to make certain that the knife is raised with sufficient slowness so as not to cause shock and stresses when it engages the knife-bar.

This particular problem of operator control has heretofore been dealt with by a system for reducing the pressure in the clam-p hydraulic system during the course of raising the clamp. However, there are certain drawbacks in such systems, in that uniform rates of upward travel cannot be obtained due to changes in friction values of the moving components. Further, mere pressure reduction `does not, theoretically as least, result in reduced upward velocity of the clamp once it has started moving. This is due to the fact that lthe speed of the clamp is dependent on cylinder area and pump capacit which are constant. Finally, mere reduction of pressure as a control expedient may not effe-ct solid engagement of the knife against its seat in the knife bar.

It is an object of the present invention to provide a system which overcomes the `drawbacks of prior art arrangements, as hereinabove described.

It is another object of the invention to provide a system which is safe in operation, economical to manufacture, and effective to provide reduced clamp speed in the course of knife-raising.

Briefly, my improved system effects clamp speed reduction by providing for restricted flow of oil from the exhaust end of the clamp pressure cylinder at the time the cylinder is in clamp-raising movement. Thus, by providing Aa reaction force that the clamp-raising piston must work against in raising the clamp, the speed of the clamp is necessarily reduced while at the same time full upward lzidh Patented Mar. l?, T964 nce pressure is realized so that the clamp will force the knife solidly against its seat in the knife bar.

A detailed description of my invention will now be given in conjunction with the appended drawing in which:

FIGURE l is a schematic of the hydraulic circuit of the machine;

FIG. 2 is a schematic electrical diagram of the control circuit of the machine; and

FIGURE 3 is a plan view partially in section showing the storage device for the knife-holding washers.

Referring now to FGURE l, a generally conventional hydraulic circuit, now known in the trade, and as shown in patent entitled Hydraulic Values for Paper Cutter, is illustrated.

No detailed `description of the hydraulic circuit is necessary except for such components as enter into coaotion with certain novel components which constitute the present invention. Thus, there are the usual valves and clamp cylinder and piston, all as designated, and it will be noted that movement of the piston to the left effects upward movement of the clamp (not shown) while movement to the right effects downward movement. When the clamp is going down, the chamber l@ of the cylinder is filled via pipe 1d through a conventional prelill check Valve while the chamber 18 exhausts via pipe 22 through the usual rn-ultiway solenoid-operated control valve 2S. The dotted lines of the valve showing the down position.

` VNoted on FIGURE 2 is the solenoid 25a which will be understood to control the clamp-operating valve 25.

There is provided the usual solenoid valve Z8, the solenoid for which is shown as 2da in FIGURE 2, and it will be understood that operation of valve 2S effects actuation of the throw-in cylinder, as shown in FIGURE l, for alternately engaging the brake and clutch (not shown) .for the knife-actuating mechanism (not shown) all of a conventional nature.

ln order to simplify for the description of the present invention, additional explanation of what is already known and conventional is minimized therein, such information being unnecessary hereto and available in my prior patents and applications as hereinabove noted, in any event.

The particularly important feature of the present invention resides in the provision of a pilot operated check valve having the valve body 31 connected intermediate the ends of the cylinder via ducts 33, 3d as shown. A solenoid operated normally open valve 36 having a solenoid 36a, as shown in FIGURE 2, is connected in duct 34 connected to intermediate cylinder chamber 1S by way of connection to duct 22. Valve body 31 contains a free piston 3S and a ball check valve 42, spring biased as shown, against its seat 42a. The casing 3l to the rear of ball check valve l2 is connected by a duct 45 via channel 45a to the chamber 47 intermediate piston 38 and ball check Valve 42 and to the clamp operating solenoid valve 25. In the position shown, valve Z5 is such that pressure fluid can pass chamber 18 for moving the clamp upwardly, when the clamp is up fluid from chamber 1l) passes through valve body 31 behind the seated ball check 42 and out of the valve body via duct 45 to valve 25. A needle valve Stb in duct 45 meters the rate of flow from chamber 10 to valve 25, from which valve oil passes to the tank via duct 52. Therefore, it will be apparent that according to the setting of the needle valve, the rate of exhaust from chamber 1h is determined, and the speed of the piston (and the clamp) governed accordingly. The valve 36 being normally open, is closed only when it is desired to meter the exhaust from chamber 10 for slowing the rate of ascent of the clamp. Thus, with valve 36 open, pressure fluid passing through duct 22 will have a certain portion of its volume bypassed through valve 36 to push piston 38 to the left, thus unseating ball check 42. Accordingly, exhaust from chamber 11i passes through the valve seat 42a into duct 45h without going through needle valve Si), and thus without restriction or metering, reaches valve 25 to exhaust to the tank. When, however, the normally open valve 36 is closed by actuation of solenoid 36a, pressure fluid in ductl22 cannot actuate piston 3S and the ball check valve is spring-biased closed, thus forcing all uid exhausting from chamber 1t) to pass through needle valve 50 which produces a resistance to movement of the clamp piston obviously slowing up the clamp.

Accordingly, although the clamp moves up slowly, full pressure is exerted, albeit at low discharge rate, and when the knife reaches the knife bar, it will be rmly seated thereagainst and held in place while the holding bolts are installed.

Referring now to FIGURE 2, the schematic diagram for the electric control circuit shows a pair of push button switches which must be pressed simultaneously with both hands of the operator and designated as LH (left hand) and RH (right hand), all in accordance with conventional practice. When the switches are in released position as shown, it will be understood that the clamp is in its top position thereby causing closure of limit switch 60 to energize relay coil CR-S. All CR-S contacts are then closed and remain closed. Depressing the push button switches serves to energize the coil of relay (2R-13 whence all contacts CR-13 are closed and the clamp valve solenoid 25a is energized as well as the coil relay CR-lti and contacts CR-Itl close. The effect of energization of the latter relay is to lock the clamp in downward position regardless of the position of the two-hand depressed operating switches. Thus, upon closure of contacts CR- and contacts CR-S, current always passes through the clamp valve solenoid 25a and through the clamp valve limit switch 64 (the clamp being in upper position and closing this switch) so that depressing the push button switches and maintaining them depressed will pass current to knife valve solenoid 28a to effect downward movement of the knife bar by control of valve 28 (FIGURE l) and the brake-clutch throw-in cylinder. When the knife bar reaches the bottom of its stroke it closes limit switch 68 thereby maintaining the knife valve solenoid 28a energized so that the knife will complete its full cycle. At top position the knife bar opens limit switch 72 thus de-energizing all the relays and solenoids above-mentioned to stop the knife at the top of its stroke.

Further, the control of the clamp is such that upon starting downward movement, the clamp limit switch 76 closes so as to energize the solenoid 80 of the vent valve (shown in FIGURE 1) to closed position, thereby permitting full pressure to be exerted on a paper pile when the clamp reaches it. At the same time that switch 76 closes the limit switch 6i) opens and the clamp starts moving downwardly. Relay CR-S cannot be energized again until the clamp returns to its top position, thereby preventing recycling of the knife, even though the push buttons are again depressed during the cycling.

To the circuitry hereinabove generally described, is added a single pole double-throw switch designated in two parts as K-1 and K-2 which are controlled by the knife holding Washers in a manner hereinbelow described but, from the diagram of FIGURE 2, it will be noted that closure of K-1 effects energization of the pilot valve solenoid 36a. At this time K-2 is open and it will be noted that this prevents current from passing to the push buttons so that itis not possible to cycle the knife. It will likewise be understood that closure of K-Z and opening of K-1 de-energizes solenoid 36a, whence valve 36 of FIGURE l is in its normally open position to unseat ball check valve 42 (FIGURE l) while the contemporaneous condition of closure of K-Z permits energization of the knife operating cycle via the push buttons. It will also be noted that the open condition of K-Z disconnects the entire operating circuit so that the clamp, as well as the knife, cannot be operated by solenoid control. However, the clamp valve 25 can, in accordance with conventional machine construction, be operated by the machine foot treadle so as to effect the position of valve 25, as shown in solid lines in FIGURE 1, in order to provide pressure duid to the clamp cylinder for raising the clamp.

FIGURE 3 shows the knife-changing washer storage device which stores the Washers so that upon removal, `automatic actuation :of switch elements K-I and K-2 is effected. Thus, `the washers 155 have screws 156 which are threaded into suitable threaded bores of the machine Iframe 158, at any desired place on the machine in some :readily accessible area, and extend through the frame to engage respective threaded adjusting pins 162 which are carried in Ia teeter bar 165. The bar 165 is carnied at its ends in slo-ts 168 orf `the sides of a str-ap 171 of U-shaped formation boilted at its feet 174 `to the frame 158. Sidewise movement of teeter bar 165 is prevented by pins 1'77 can-tied thereby and engageable with the sides of the slots 168, as will be understood from FIGURE 3. Thus, pins 177 are spaced slightly away from the sides of the slot to permit a predetermined degree of rocking of bar 165. Carried by the intermediate portion of the strap 171 is the switch arrangement K-l and K-Z, generally desig- Ira-ted by the housing and shown in a diagrammatic manner as having a spring biased rod or pin 1'33 which resiliently' abuts the center of bar 165 and maintain engagement olf pins 177 with the 'washer screws. The rod 183 canries the center pole of the switch combination and it will be understood that when pin 183 is in the position shown K-l is closed land K-Z is open to conform to the condition of FIGURE 2. However, should either Washer be removed, the end of `the bar 165 supported thereby will drop, thus, dropping rod 183, whence K-l will `open `and K-Z ywill close. The center pole of the switch as shown in FIGURE 3, conforms, of course, to fthe direct connection shown between the two switches K-1, I-Z on FIGURE 2.

An alternative arrangement would be to lhave switch K-l `operated directly olf the foot treadle so that Iany time the foot treadle is depressed, lthe cllamp will slowly rise. Thus, [the safety arrangement of FIGURE 3 would involve only that portion of lthe sw-itch designated K-Z. In s-uch case, full release of the foot treadle would permit K-ll to open, for example, for rapid rise of the clamp,

Having thus `described my invention, I am aware that various changes may be made without departing from the spirit thereof and, accordingly, I do not seek to be limited to the precise illlus-trations herein given, except as set forth in the appended claims.

What is claimed is:

l. In a knife-changing control system for a guillotine type paper cutter having ya hydraulically operated clamp, a hydraulic double-ended cylinder and piston therein for actuating said clamp to up and down position, and means for effecting restricted dow from the exhausting end of said cylinder when said clamp is being moved upwardly by' power of said piston, said means comprising a valve biased to closing position and a passage leading from an end of said cylinder to one side of said valve, and a passage leading from the other side of said valve, whereby olw may be substantial-ly unrestricted past said valve when said valve is open, a pressure operable valve operating piston element disposed` upon `actu-ation to open said valve, a restricted flow passageway on the saine side of said valve as said first-mentioned passageway, means for effecting pressure on said valve operating piston for maintaining said valve normally open, and means for removing pressure from said valve operating piston whereby said valve automatically closes to effect movement of exhaust;

fluid :from said cylinder through said restricted flow passageway at a predetermined reduced rate whereby the K full pressure vaching lin said cylinder is utilized to main- References Cited in the le of this patent tain said clamp in raised position.

2. In a system `as set forth fin claim 1, Said latter means UNITED STATES PATENTS 

1. IN A KNIFE-CHANGING CONTROL SYSTEM FOR A GUILLOTINE TYPE PAPER CUTTER HAVING A HYDRAULICALLY OPERATED CLAMP, A HYDRAULIC DOUBLE-ENDED CYLINDER AND PISTON THEREIN FOR ACTUATING SAID CLAMP TO UP AND DOWN POSITION, AND MEANS FOR EFFECTING RESTRICTED FLOW FROM THE EXHAUSTING END OF SAID CYLINDER WHEN SAID CLAMP IS BEING MOVED UPWARDLY BY POWER OF SAID PISTON, SAID MEANS COMPRISING A VALVE BIASED TO CLOSING POSITION AND A PASSAGE LEADING FROM AN END OF SAID CYLINDER TO ONE SIDE OF SAID VALVE, AND A PASSAGE LEADING FROM THE OTHER SIDE OF SAID VALVE, WHEREBY FLOW MAY BE SUBSTANTIALLY UNRESTRICTED PAST SAID VALVE WHEN SAID VALVE IS OPEN, A PRESSURE OPERABLE VALVE OPERATING PISTON ELEMENT DISPOSED UPON ACTUATION TO OPEN SAID VALVE, A RESTRICTED FLOW PASSAGEWAY ON THE SAME SIDE OF SAID VALVE AS SAID FIRST-MENTIONED PASSAGEWAY, MEANS FOR EFFECTING PRESSURE ON SAID VALVE OPERATING PISTON FOR MAINTAINING SAID VALVE NORMALLY OPEN, AND MEANS FOR REMOVING PRESSURE FROM SAID VALVE OPERATING PISTON WHEREBY SAID VALVE AUTOMATICALLY CLOSES TO EFFECT MOVEMENT OF EXHAUST FLUID FROM SAID CYLINDER THROUGH SAID RESTRICTED FLOW PASSAGEWAY AT A PREDETERMINED REDUCED RATE WHEREBY THE 